If you buy something for a couple of pounds and take your order over £600, you can use the PERKZ40NEW code, this will give you £40 off.You should get it for around the £530 mark then.
Guess they must have got wise to people putting on multiple codes.
I added some batteries to take me to £600.99.
Applied the £40 PERKZ40NEW one first then the DEC30 but the system replaced the £40 discount with the £30 one instead of taking them both off so the price went up!
Any hints to get round that would be much appreciated.